The short answer
Tesamorelin is a synthetic analogue of human growth-hormone-releasing hormone: the full 44-amino-acid sequence with a trans-3-hexenoyl group on the N-terminal tyrosine, added to slow enzymatic degradation. Developed by Theratechnologies as TH9507, it was approved by the FDA in 2010 as Egrifta for HIV-associated lipodystrophy, making it the only GHRH analogue holding a marketing approval.
Key facts
- Class
- GHRH analogue
- Structure
- All 44 GHRH residues + trans-3-hexenoyl group
- Mass
- 5,135.9 Da
- CAS
- 218949-48-5
- PubChem
- CID 16137828
- Developer
- Theratechnologies, code TH9507
- Approval
- FDA 2010, as Egrifta (US)
- UK status
- No UK licence; research use only
What the hexenoyl group changes
Native GHRH survives minutes in circulation: DPP-4 clips the first two residues and the fragment is inactive. The tesamorelin peptide answers that with a trans-3-hexenoyl group fixed to the N-terminal tyrosine, which shields the cleavage site while leaving every amino acid of the natural hormone in place. Slower degradation, same sequence: that is the entire design.
The full sequence, not a fragment
The other GHRH peptides in research catalogues are fragments. Sermorelin and Modified GRF (1-29), the CJC-1295 family's base, keep only the first 29 residues, because receptor activation lives in that region. Tesamorelin keeps all 44. The tail is not required for agonism, but it makes the molecule the closest synthetic copy of the native hormone, and it is why papers on tesamorelin peptides read across to GHRH biology more directly than fragment studies do.
Research material referenced
Tesamorelin 5mg, third-party HPLC tested
One molecule, several names
TH9507 in the development papers, tesamorelin as the generic name, Egrifta on the pharmaceutical label, and testamorelin in a common misspelling that search engines quietly forgive. All refer to the same 5,135.9 Da molecule, CAS 218949-48-5, PubChem CID 16137828. A certificate or paper that cannot be reconciled to those identifiers is describing something else.
The FDA file, and the pen
The FDA approved tesamorelin in 2010 for excess visceral abdominal fat in HIV-associated lipodystrophy, on two phase 3 programmes measuring visceral fat by CT. The pharmacy product has since moved through Egrifta SV and Egrifta WR presentations, supplied as patient injection kits, which is what searches for a tesamorelin pen are finding. Research vials and pharmaceutical kits are different articles: one is a licensed medicine in the United States, the other is laboratory material.
Where it stands in the UK
Egrifta's authorisation is American. Tesamorelin holds no UK or EU marketing authorisation, is not a controlled drug in the UK, and is supplied here as freeze-dried powder for laboratory research only. Nothing on this page or this site is a medical claim; the approval history is cited because it is the reason this compound has human trial data at all.
Quick reference
| Analogue | Residues | Modification | Approval |
|---|---|---|---|
| Tesamorelin | 44 | Hexenoyl group on Tyr1 | FDA 2010 (US, as Egrifta) |
| Sermorelin | 29 | None (GRF 1-29) | Former US approval, withdrawn |
| Mod GRF (1-29) | 29 | Four substitutions | None |
| CJC-1295 with DAC | 29 | Substitutions + albumin linker | None |
Frequently asked questions
- Is tesamorelin the same as Egrifta?
- Same molecule. Egrifta is the US pharmaceutical brand; tesamorelin is the generic name. Research vials are not the pharmaceutical product.
- Is tesamorelin a peptide?
- Yes. The tesamorelin peptide is 44 amino acids, the full GHRH sequence, with a hexenoyl group on the first residue. At 5,135.9 Da it is among the larger compounds in this catalogue.
- Is testamorelin something different?
- No, it is a misspelling of tesamorelin. There is no separate compound by that name.
- Is tesamorelin licensed in the UK?
- No. The FDA approval does not extend to the UK or EU. It is sold here for laboratory research only.
Continue researching
Peer-reviewed guides, comparators and matched reference materials.
Primary sources & clinical trials
Peer-reviewed research and registered trials from PubMed, ClinicalTrials.gov, PubChem, FDA and NIH. All links open in a new tab and point to the primary source, so every claim can be verified at origin.
- FDADailyMed, EGRIFTA WR (tesamorelin) prescribing informationdailymed.nlm.nih.gov
- PubChemPubChem, Tesamorelin (CID 16137828)pubchem.ncbi.nlm.nih.gov
- PubMedFalutz J et al., Metabolic effects of a growth hormone-releasing factor in patients with HIV. N Engl J Med 2007 (PMID 18057338)pubmed.ncbi.nlm.nih.gov
- PubMedFalutz J et al., Tesamorelin pooled phase 3 analysis. J Clin Endocrinol Metab 2010 (PMID 20554713)pubmed.ncbi.nlm.nih.gov
- PubMedStanley TL et al., Tesamorelin, visceral fat and liver fat in HIV. JAMA 2014 (PMID 25038357)pubmed.ncbi.nlm.nih.gov
- GuidelineGoogle: Creating helpful, reliable, people-first contentdevelopers.google.com
Written and reviewed by
William Heath · Editor, UK Peptides research library
William Heath edits the UK Peptides research library. He is responsible for what is published here: every article is sourced to primary literature, every purity or identity statement traces to a signed third-party certificate for a specific lot, and corrections are made in place with the review date updated. No scientific or medical credentials are claimed on this site; the evidence is carried by the cited sources and the certificates, not by the byline.
More Tesamorelin (GHRH Analogue) articles
- Tesamorelin Dosage: What the Published Trials UsedEvery tesamorelin dosage figure traces to one number: 2mg daily in the phase 3 trials. Where the charts and calculators come from, and what a research vial is.
- Tesamorelin Before and After: What the Trials MeasuredBefore-and-after tesamorelin results in the trials were CT scans, not photos: visceral fat fell roughly 15% over 26 weeks, then returned after stopping.